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arXiv · 2503.11890

Spectroscopic signatures of biexcitons: A case study in Ruddlesden-Popper lead-halides

Katherine A. Koch·Esteban Rojas-Gatjens·Martin Gomez-Dominguez·Juan-Pablo Correa-Baena·Carlos Silva-Acuna·Ajay Ram Srimath Kandada
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Abstract

Exciton-exciton interactions are fundamental to the light-emitting properties of semiconductors, influencing applications from lasers to quantum light sources. In this study, we investigate the spectroscopic signatures and binding energy of biexcitons in a metal halide two-dimensional Ruddlesden-Popper structure, which is known for hosting distinct excitonic resonances with unique lattice coupling. Using three spectroscopic techniques - photoluminescence (PL) and two variations of two-dimensional electronic spectroscopy (2DES) - we map coherent one-quantum and two-quantum correlations to gain deeper insight into the biexciton characteristics. While PL spectroscopy is hindered by spectral broadening and reabsorption, 2DES provides a more accurate characterization, revealing multiple biexciton states and uncovering a mixed biexciton species arising from exciton cross-coupling. These findings highlight the importance of advanced spectroscopic approaches in accurately determining biexciton binding energies and offer new perspectives on many-body interactions in exciton-polarons within layered perovskites.

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Katherine A. Koch, Esteban Rojas-Gatjens, Martin Gomez-Dominguez, Juan-Pablo Correa-Baena, Carlos Silva-Acuna, Ajay Ram Srimath Kandada. 2025-03-14. Spectroscopic signatures of biexcitons: A case study in Ruddlesden-Popper lead-halides. https://doi.org/10.1063/5.0271075

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